Abstract
The present study aims to assess the phenology, biomass, chemical composition and nutritional value of Potamogeton crispus L. in the water courses of Nile Delta, Egypt. The sampling process was carried out seasonally using 60 quadrats each of 1 x 1 m distributed along 13 irrigation and two drainage canals in 5 locations of the area under study. Growth of P. crispus was markedly seasonal, starting in autumn and reaching the maximum phytomass yield in spring (400 g DM m(-2)). The mean biomass of the drainage canals (238 g DM m(-2)) was significantly lower than that of the irrigation canals (399 g DM m(-2)). The concentrations of P, Ca, Mg and Na in P. crispus were highest at the beginning of the growing season (autumn) and decreased throughout the population growth, while Mn and Cu showed the opposite trend. In addition, the concentrations of Mg, Pb and Zn in this plant in the drainage canals were significantly higher than those in the irrigation canals. The nutritive values of P. crispus are within the range of feed nutritive value for sheep, goat, dairy and beef cattle. P. crispus could be considered as a nutrients and heavy metals remover for wastewater treatment if it is harvested during its peak of biomass production. As feed supplement for animals and waterfowl, this plant could be considered excellent because of its high levels of total carbohydrate, total protein, digestible crude protein, total digestible nutrients and the lower crude fibre contents, provided that the concentration of heavy metals is not above the nutritional thresholds.